With a population of 556,000 residents, Union has achieved one of the lowest COVID-19 community transmission rates in the nation, according to the Centers for Disease Control and Prevention.

The CDC examines data from thousands of counties across the country, determines their level of community spread and classifies them based on transmission risk: high, substantial, moderate or low.

It’s the only county in the state to achieve the “lowest tier for community transmission” for COVID-19, the county said in a statement on Thursday.

“I think we took COVID-19 serious from day one,” said Union County Commissioner Board Chairman Alexander Mirabella.

Nearly 80,000 residents have been infected so far, with more than 1,800 deaths — the sixth highest number in the state, according to the New Jersey COVID-19 dashboard.

Union borders Essex County, which has suffered the most coronavirus fatalities in the state, and Middlesex County, which has suffered the third-highest deaths.

Looking at the CDC’s map, it’s curious to see an entire state covered in red and orange — counties labeled as having “high” and “substantial” rates of community transmission — and then seeing a single, tiny blue square signifying low risk.

The CDC calculates community transmission by looking at total new cases for every 100,000 residents over the past seven days, and the percentage of positive tests over the past seven days.